Friends Mourn TV Legend Merv Griffin

The loss of television mogul Merv Griffin on Sunday is being mourned by generations of fans and friends – from American Idol host Ryan Seacrest to former first lady Nancy Reagan.

"Merv was a dear friend, a mentor and my idol. He gave me my first break into show business, and for that I will forever be grateful. Merv is a true legend and will continue to be an inspiration," Seacrest, 32, told PEOPLE about the onetime talk-show host and game-show producer who died of prostate cancer at age 82.

Another TV personality who owed much of his career to Griffin was Pat Sajack, 60, the longtime host of Wheel of Fortune, which Griffin produced. "I'm dealing with deep sadness and the realization that I will never hear that wonderful laugh of his again," Sajack said Sunday. "He meant so much to my life, and it's hard to imagine it without him."

Mrs. Reagan, 86, who had known Griffin for more that 50 years, "is deeply saddened at the death of her friend who had helped her through the pain of losing her husband to Alzheimer's disease," her spokeswoman said Sunday.

"They knew each other in Hollywood, but became close when [Ronald Reagan] was President. and very close in the post-Presidential years when the President became ill," the spokeswoman told PEOPLE.

As for Mrs. Reagan, "She is taking it very hard. It is very difficult for her. He was her strength; he was her knight in shining armor."

Zsa Zsa Gabor, 90, a frequent guest on Griffin's 1960s talk show (and the great step-aunt of Paris Hilton), also issued a statement, saying, "I'm very upset at the news. He was a very close friend of ours, a good friend of mine and a good friend of Eva's," she said, referring to her late sister, Green Acres star Eva Gabor, who at one time was said to be engaged to marry Griffin. "He was just a wonderful, wonderful man."

President and Mrs. Bush also expressed their sadness over Griffin's death. In a statement, Bush said, "For over half a century, Merv Griffin entertained America. He was a man of innovation and energy who greeted challenges with laughter and determination."

Griffin, who was divorced from ex-wife Julann Griffin, is survived by a son, Tony Griffin, a daughter-in-law Tricia, and two grandchildren, Farah and Donovan Mervyn.

Griffin's family is holding a private funeral service this Friday, followed by a reception at the Beverly Hilton.